Last night and the night before I went though the simple process of moving my websites over from slicehost to Linode. The moved went smoothly and I’m happy with the new provider.

I had been with slicehost for over a year now and they’ve provided a fantastic service, only ever had my VPS go down once due to a faulty server box I was on. Slicehost have a really nice clean control panel too which was very easy on the eye and simple to manage.

However, all of slicehost’s packages are for 64bit systems – no 32bit option offered. I’ve been looking to head back to 32bit to cut down on the memory consumption in a couple of Merb applications (as you know pointers are 64bit on a 64bit OS and Ruby makes use of pointers quite often). Linode allow you to choose 32bit and because of this I have managed to take my total memory usage of around 420mb down to 218mb with room to breath which has allowed me to drop down to a cheaper package, at least for now.

Linode so far have also been fantastic. The Linode control is a little more ‘full’ than the Slicehost one but after a few minutes of getting to know your way round it’s soon manageable and dare I say nicer, in the way it makes you feel like you’re in ‘more control’ over your server. Linode servers also felt a fair bit quicker, installing stuff seemed snappier and it feels like I get less delay when connecting via SSH – this could be down to the fact I was given a choice of data center and opted for one on the east coast.

On a side note, Linode also offer slighty higher memory, bandwidth and disc space for the same price that slicehost do. For example on the base package of $20 gets you 256mb ram, 100GB monthly bandwidth and 10GB of disc storage with Slicehost compared to the 360mb ram, 200GB bandwidth and 12GB storage you get with Linode.

Conclusion

So in conclusion I would highly recommend both hosts, I can’t comment on Linode up-time wise but so far they’ve been amazing had my slice within minutes of buying, the server seem quick lots of configuration options right down to which data center you wish to be placed into. Slicehost have been fantastic up-time wise the control is sleek and the packages reasonable.

I would personally recommend Linode if you’re trying to save a bit of cash and would like the 32bit option to get that little bit extra memory saving.

I’ve written a simple backup script in Ruby that utilises Rsync I’ve made it public so feel free to fork, change and contribute!

The backups are structured as such:

/remote/location/current – The current folder contains the the latest clone of the intended backup folder.
/remote/location/backup_dir – The backup directory, which by default is the current day (monday, tuesday, etc) contains
the difference to current since it was last run. So it will contain any new files and any files that were deleted.

I need to add a few examples of the settings and how to use it via cron on Linux and Launchd on OS X but the basic script should be working fine.

The script can be found on my github account, http://github.com/RichGuk/rrsync/tree/master

You can simply clone it with the following command:

git clone git://github.com/RichGuk/rrsync.git

Today I decided to setup Xen (not the Half-Life world) on a clean Debian installation so I could have a few VPSes to play around with load balancing mySQL, FastCGI and Mongrel. I thought I’d break down the steps I went though to get the basic Xen setup working.

Note: This is by no means a perfect setup, it’s more of a quick way to play around with Xen using a spare PC in the home. If you want more of a production level setup I suggest checking out the Xen website, or Google.

Step 1. Install Debian (Etch)

Here you just need to setup a standard Debian system, I’m using the 64bit edition of Etch but the process is the same for most Debian releases. I won’t go into detail on how to setup Debian as there are plenty of how-tos out there, for me the normal setup was fine. During the installation I gave the machine judgement as the hostname and gnet.foo as the domain (you can use whatever) I also unchecked desktop from the selectable software menu as I didn’t need/or want a GUI.

Step 2. Configure Debian ready for Xen

Once you’ve booted and logged into your system you need to install a few applications, but before we do that I tend to remove the CD source from apt-get’s sources.list:

vim /etc/apt/sources.list

#comment out the CD line
#deb cdrom:[Debian...........
apt-get update

Now install the packages (remove vim-full if you're not using vim):

apt-get install ssh build-essential vim-full

Next we need to configure the server to use a static IP (if you didn't during the installation). I gave my box (judgement) a static IP of 192.168.1.10. Open up the interfaces file:

vim /etc/network/interfaces

Now if you selected DHCP during the installation your file should look similar to this by default (eth2 was my interface, yours might be different):

allow-hotplug eth2
iface eth2 inet dhcp

Change yours to match this (of course change eth2 to match yours and whatever IP you wish to use):

auto eth
iface eth2 inet static
address 192.168.1.10
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.1

Once you've done that you need to restart the networking:

/etc/init.d/networking restart

If all is working then you should be able to ping other computers on your network and they should be able to ping your machine.

If you wish you can continue the rest of the setup via SSH (on windows you can use Putty).

Finally just make sure your system is up-to-date before giving it a reboot:

apt-get upgrade
shutdown -r now

Step 3. Installing Xen

There are two main options when it comes to installing Xen. You can compile it from the source code or simply use apt-get, the latter worked fine for me and is dead simple...to install via apt-get use the following command (bridge-utils is used to setup the network for the virtual machines):

apt-get install xen-linux-system-2.6.18-6-xen-amd64 bridge-utils

The version of Xen kernel might of changed since writing this, try this command to see what's there:

apt-cache search xen-linux

When that has finished installing give the machine a reboot and select Xen kernel from the GRUB menu (for me it became the default option):

shudown -r now

Once the system is back up and logged in (your previous credentials should work) check that you've booted the correct kernel:

uname -r

It should read something like 2.6.18-6-xen-amd64 if not then you've most likely booted the wrong kernel from GRUB.

Step 4. Creating virtual images or DomU's (the VPSes)

To help with creating, starting, stopping, etc... you need to install xen-tools:

apt-get install xen-tools

Next we need to create the place we want to store the domains (virtual servers), I put mine in /home/xen (xen requires a folder called domains within this folder) so run this command:

mkdir -p /home/xen/domains

Once you've created the location to store the domains you need to edit a few options in Xen's configuration. Start by opening up xend-config.sxp:

vim /etc/xen/xend-config.sxp

and look this for line (around line 70 for me):

##
# To bridge network traffic, like this:
#
# dom0: fake eth0 -> vif0.0 -+
#                            |
#                          bridge -> real eth0 -> the network
#                            |
# domU: fake eth0 -> vifN.0 -+
#
# use
#
# (network-script network-bridge)

and uncomment the network-script network-bridge part so it looks like this:

##
# To bridge network traffic, like this:
#
# dom0: fake eth0 -> vif0.0 -+
#                            |
#                          bridge -> real eth0 -> the network
#                            |
# domU: fake eth0 ->; vifN.0 -+
#
# use
#
(network-script network-bridge)

Now we need to setup some defaults as well as the location to store the domains by opening up xen-tools.conf:

vim /etc/xen-tools/xen-tools.conf

There are several things to comment out and change here so I'll just list the values I changed in mine:

...
dir = /home/xen
...
debootstrap = 1
...
dist = etch
#If you want to give your domains static IP's rather than use DHCP (which I did then you can setup the default gateway/netmask)
gateway = 192.168.1.1
netmask = 255.255.255.0
...
#This bit is important, as mine differed to the default you need to change kernel and initrd to point to the right ones (ls /boot/* - to find out)
kernel = /boot/vmlinuz-2.6.18-6-xen-amd64
initrd = /boot/initrd.img-2.6.18-6-xen-amd64
...
#Change this to your prefered mirror (for me that's the UK):
mirror = http://ftp.uk.debian.org/debian/

Restart Xen to make sure the configuration loads correctly:

/etc/init.d/xend restart

You should now be ready to create your first domain. If you're happy with the defaults in the xen-tools.conf file then you can leave a lot of the options out or you can of course put them as arguments of the command, check the man pages for xen-create-image for more information:

xen-create-image --hostname=i-am-webial --ip=192.168.1.11 --netmask=255.255.255.0 --gateway=192.168.1.1 --passwd

You should see output of something like this:

General Infomation
--------------------
Hostname       :  i-am-webial
Distribution   :  etch
Fileystem Type :  ext3

Size Information
----------------
Image size     :  4Gb
Swap size      :  128Mb
Image type     :  sparse
Memory size    :  128Mb
Kernel path    :  /boot/vmlinuz-2.6.18-6-xen-amd64
Initrd path    :  /boot/initrd.img-2.6.18-6-xen-amd64

Networking Information
----------------------
IP Address 1   : 192.168.1.11
Netmask        : 255.255.255.0
Gateway        : 192.168.1.1

Creating swap image: /home/xen/domains/i-am-webial/swap.img
Done

Creating disk image: /home/xen/domains/i-am-webial/disk.img
Done

Creating ext3 filesystem on /home/xen/domains/i-am-webial/disk.img
Done

Installing your system with debootstrap mirror http://ftp.uk.debian.org/debian/
....
....
....

Once it's finished you can start your domain by using the following command:

xm create /etc/xen/i-am-webial.cfg

Extra Stuff

Open a console for the domain:

xm console i-am-webial

you can exit the console by doing Ctrl + ].

To shutdown a domain:

xm shutdown i-am-webial

Increase the RAM of the domain:

vim /etc/xen/i-am-webial.cfg

find and edit memory

memory  = '512'

Resize the swap to 1GB (Resize Xen DomU swap):

cd /home/xen/domains/i-am-webial
dd if=/dev/zero of=swap.img bs=1024k count=1024
mkswap swap.img

Expand the file system by 4 GB (Resize Xen DomU disk)

dd if=/dev/zero bs=1GB count=4 >> disk.img
resize2fs -f disk.img

Hopefully you should now all be setup with basic VPSes, if you need any help with problems please feel free to contact me. You may also leave any feedback/comments you wish below.

So the other day I decided to switch from using Apache to Nginx not because apache isn’t any good, far from it. Nginx just uses much less ram and when you’re on a fairly small slice, using up more ram just isn’t good. I was going to benchmark speed and things between apache and nginx but I forgot to take some readings before stopping the apache service and installing nginx so we’ll skip over that idea like the thought never came into my head.

I’ll mention a few things I like about nginx first:

1. It’s Russian -Being Russian it makes me feel like a communist, which is fun. It also reminds me of being build to take all things thrown at it.
2. It uses a lot less memory – As I said before, not really done much benchmarks so these were some quick figures from ‘top’ but I had apache running with about 5 instances each using 2-3% of ram even at 2% each that’s still 10% of ram being used just for apache… with nginx I appear to have 2 instances running both using 0.2% of ram, so 0.4% in total – which is a nice difference.
3. Faster page serving - Now this is meant to be a server fast at serving static content so its not just be me but I find the site much quicker compared to when it used to be on apache (all the sites in fact). I’m not to sure if I just think it’s quicker, the slice has more ram free so never going into swap or…. it is just a lot quicker at serving pages.

Read the rest of this entry »

Off to see Kerry at aber this weekend so thought I’d pump out a quick youtube Friday before I head off.

First off I thought I’d start with the Floyd, this is from division bell, which is one of my favourite Pink Floyd album.

Next up a bit of Thom, not to sure if I’ve posted this before – I have yet to import posts from the old blog. I’m sure you can survive having to watch it again…..after all it is Thom

Finally I thought I’d post this video I found, I was orginally going to find Bob’s version, and then the one thats playing at the end of the last season of Battlestar Galactica but instead I found this insane child playing it like a pro. Enjoy (All along the watch tower btw).